Batteries such as an alkali rechargeable battery and a lithium ion rechargeable battery are widely used as the power supply of a portable device, a power tool, or an electric vehicle. Typical methods for manufacturing electrodes thereof include one in which powder materials are filled into a three-dimensional porous metal body as with the positive electrode of an alkali rechargeable battery, and one in which an electrode mixture paste formed by kneading powder materials is applied to a core made of a metal thin plate as with the positive and negative electrodes of a lithium ion battery and the negative electrode of a nickel metal hydride battery. Among these electrode manufacturing methods, the latter application technique has particularly high productivity, and is thus applied regardless of the battery type. For high-efficiency manufacturing methods, there have also been proposed various types of manufacturing methods, including multi-row application (for example, see patent document 1 and patent document 2).
In the method of applying an electrode mixture paste to both sides of a core, the electrode mixture paste applied is dried to make an electrode hoop. Subsequently, as shown in FIG. 3, the electrode hoop 21 is mounted on an uncoiler unit 23 of a rolling system in the form of an electrode coil 22 wound in a coil shape. It is unwound by the uncoiler unit 23, and fed to a rolling unit 25 consisting of a pair of mill rolls 26a and 26b via a guide roll 24, whereby the electrode mixture layers 21b applied to both sides of the core 21a are rolled. It should be appreciated that the electrode mixture layers 21b on both sides are usually set to an identical thickness C. The electrode hoop 21 rolled by the rolling unit 25 is fed to a coiler unit 28 via a guide roll 27, thereby being wound up and taken out in a coil form.
Positive and negative electrodes fabricated thus are wound with a separator interposed therebetween to form an electrode assembly, which is inserted into a metal battery case before an electrolytic solution is poured in to make a desired battery.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-297756
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2002-304988